2-(3-Methyl-2-oxoquinoxalin-1-yl)-N-(4-methylphenyl)acetamide

Chains extending along the b-axis direction are formed through hydrogen bonding between the amide functions of the title quinoxaline derivative.


data reports
Synthesis and crystallization 1.00 g (6.24 mmol) of 3-methylquinoxalin-2(1H)-one was dissolved in 25 ml of dimethylformamide and 1.15 g (6.24 mmol) of 2-chloro-N-(p-tolyl)acetamide were added, followed by 1.0 g (7.5 mmol) of potassium bicarbonate, and a spatula tip of BTBA (benzyltributylammonium chloride) was used as a phase-transfer catalyst. The reaction was stirred for 2 h under reflux at 353 K. When the starting reagents had completely reacted, 500 ml of distilled water were added and a few minutes later the product precipitated. This was filtered off, dried and recrystallized from hot ethanol solution to yield light-yellow plate-like crystals of the title compound.

Refinement
Crystal, data collection and refinement details are presented in Table 2. H atoms attached to carbon were included as riding A portion of one ribbon, viewed along the a-axis direction, with N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds depicted, respectively, by violet and black dashed lines. Non-interacting H atoms have been omitted for clarity.

Figure 3
The packing, viewed along the b-axis direction, with intermolecular interactions depicted as in Fig. 2 and non-interacting H atoms omitted for clarity.
atoms in idealized positions with isotropic displacement parameters tied to those of the attached atoms, while that attached to nitrogen was refined independently. Analysis of 446 reflections having I/(I) > 20 and chosen from the full data set with CELL_NOW (Sheldrick, 2008) showed the crystal to belong to the monoclinic system and to be twinned by a 180 rotation about the c* axis. The structure was refined as a twocomponent twin. The two components [0.503 (2): 0.497 (2) ratio] of the disordered C12-C17 ring were refined as rigid hexagons.

2-(3-Methyl-2-oxoquinoxalin-1-yl)-N-(4-methylphenyl)acetamide
Crystal data Special details Experimental. The diffraction data were obtained from 16 sets of frames, each of width 0.5° in ω or φ, collected with scan parameters determined by the "strategy" routine in APEX4. The scan time was θ-dependent and ranged from 5 to 10 sec/frame. Analysis of 446 reflections having I/σ(I) > 20 and chosen from the full data set with CELL_NOW (Sheldrick, 2008) showed the crystal to belong to the monoclinic system and to be twinned by a 180° rotation about the c* axis. The raw data were processed using the multi-component version of SAINT under control of the two-component orientation file generated by CELL_NOW. Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. H-atoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.99 Å) and were included as riding contributions with isotropic displacement parameters 1.2 -1.5 times those of the attached atoms. That attached to nitrogen was refined independently. Refined as a 2-component twin. The C12···C17 ring is rotationally disordered over two sites in a 0.503 (2)/0.497 (2) ratio. The two rings were refined as rigid hexagons.